Hi Everyone, I see that problems with MP4 playback are fairly common but I couldn't find a solution to my problem in any of the several questions and answers I've reviewed. When I comment out the OGG code at http://www.deiryassin.org/video.html I cannot get the MP4 file to play. The OGG file play back in Firefox is just fine. Someone else who uses the latest version of Safari for the Mac OS was not able to get reliable MP4 playback, either. Per w3schools.com, MP4 is a supported fiie type in both Safari and Firefox. I don't know how to embed HTML in this question so please see the attached PNG file for the code I used for testing MP4 playback. The MP4 file location is correct and the file is not corrupted, it plays fine when I download it. When I try to play it in Firefox the browser console/error log says: "Specified 'type' attribute of 'video/mp4' is not supported. Load of media resource /media/deiryassinremembered.mp4 failed." The browser displays: "No video with supported format and MIME type found". Here are the codecs for the file: Codec: H264 - MPEG-4 AVC (part 10) (avc1) Codec: MPEG AAC Audio (mp4a) The following lines are in my .htaccess: AddType video/mp4 mp4 m4v AddType audio/mp4 m4a I've re-enabled the OGG source for visitors to the site. Any ideas on what I'm doing wrong? Thanks.